Sending DatagramPacket with no internet connection - Android

Question

I'm using the following code to send DatagramPacket to a given address:

InetAddress address = InetAddress.getByName(anIPAddress);

DatagramSocket socket = new DatagramSocket();
DatagramPacket packet = new DatagramPacket(packetBytes, packetBytes.length,
    address, port);

socket.send(packet);
socket.close();

It works fine, but how come this code does not throw any Exception when there's no internet connection available?

I turn off both Wi-Fi and mobile data, and this code still gets executed without any errors.

Is there a way to ensure that the packet is actually sent?

(i don't care if it's reached the destination or not, i'd just like to make sure it is sent)

Answer 1

You can use NetworkInterface.getNetworkInterfaces(); to check what interfaces are available. Then you can check with ni.isUp().

Enumeration<NetworkInterface> nets=NetworkInterface.getNetworkInterfaces();
for(int i=0; nets.hasMoreElements(); ++i) {
    NetworkInterface ni=nets.nextElement();
    if (ni.isUp() && !ni.getName().equals("lo")) {
        //ni is not local
        break;
    }
}